To answer:
A) Apparently other people working on Trump’s legal team did not feel her claims were credible. She has been giving interviews to very pro-Trump media outlets (stuff that makes FOX News look like the BBC) promising evidence for a massive criminal conspiracy that would rival the most far-out conspiracy theories about the JFK assassination, the moon landing and 9/11.
–I would also not be surprised if Rudy Guiliani resented her, because he LOVES to be the center of attention. Rudy is also part of Trump’s inner circle – and they have known each other for years – while Powell is a recent addition to the team, being the attorney for Trump’s first National Security Advisor, General Michael Flynn (the guy who was deeply connected to Russia and charged, pled guilty and then retracted his guilty plea). In the 1980s, Rudy Guiliani was a very successful Federal prosecutor in New York City. Former FBI Director James Comey recounted that when he worked for Guiliani, the most important thing was that Guiliani was ALWAYS the center of attention – “There was something of an unwritten code about working in the office of Rudy Giuliani,” Comey observed. “In his case, the message was that Rudy was the star at the top and the successes of the office flowed in his direction. You violated this code at your peril.”
B) Sidney Powell never really has to provide any evidence at all. There is a certain segment of the population that wants to buy what she is selling. She is playing to a select audience. The majority of Americans do not even know who she is, and for most of the rest, she was just someone working with Rudy Guiliani for Trump. She is trying to play to a base of hard core, dedicated, fervent MAGA – Trump fans who have already bought in to this global conspiracy stuff.